The Justice League of America uses the occasion of its third anniversary to tell Snapper Carr and Green Arrow about the formation of the League, involving the discovery of strange meteors that nearly doomed them forever. When seven meteors are sent to Earth by aliens from the planet Appellax, six superheroes of our world individually overcome the beings that emerge from them. They then come together to combat the seventh menace and vow to form the Justice League of America.

Scientist Palmer is experimenting with his reducer lens to try and reduce objects in size without blowing them up, all without success. However, when he, Jean and students are trapped in a cave-in, he decides to use the lens on himself and save the others before he is destroyed. To his surprise, he is not destroyed as he becomes a human atom, and the lens later returns him to normal size.

Recap of Superman's life beginning with his escape from the destruction of Krypton, through his adoption and raising by the Kents, his training and career as Superboy, up to his leaving Smallville for Metropolis and joining the Daily Planet after the deaths of his adoptive parents.